|  | 7.4 | Novell IPX Configuration
| 7.4.2 |
Writing a valid IOS command sequence to assign IPX network numbers to interfaces

When assigning IPX network numbers to interfaces that support multiple IPX networks, you can also configure primary and secondary IPX networks. The first logical network you configure on an interface is considered the primary network. Any additional networks are considered secondary networks. Again, each IPX network on an interface must use a distinct encapsulation, and it should match that of the clients and servers using the same network number. Assigning the second network number is necessary if an additional encapsulation type is linked to an individual network. To assign network numbers to interfaces that support multiple IPX networks, you normally use subinterfaces. A subinterface is a mechanism that allows a single physical interface to support multiple logical interfaces or networks. That is, several logical interfaces or networks can be associated with a single hardware interface. Each subinterface must use a distinct encapsulation, and the encapsulation must match that of the clients and servers using the same network number. The example shown in the Figure illustrates both the global configuration of Novell IPX and the assignment of network numbers to interfaces. The information in the table describes the commands used in the example.
| Threaded Case Study
Washington Project: Configuring Subinterfaces

If a router's interface needs to exist on two different IPX networks to accommodate two different frame types or two different IP subnets, or if you run out of host space, then you need to configure subinterfaces.